5.1. Introduction

Proteins are the ultimate functional product of
most gene expression so optimally one would prefer to look at proteins when
trying to understand the mechanisms an organism uses to respond to a given
condition. As with any other biomolecule, tools for identifying and quantifying
proteins are a prerequisite to their successful study. Single proteins are
typically detected using antibodies but very few antibodies have been generated
against bee proteins and none have been commercialized. Of all the analytical
methods available for studying proteins, mass spectrometry is the most
sensitive, most accurate and least biased. Proteins can be identified by mass
spectrometry by first hydrolyzing them with a specific protease such as trypsin.
The masses and fragmentation patterns of the resulting peptides can then be
determined and used to identify the peptides individually and the protein(s)
they came from (i.e. proteomics). This process works best when all possible
proteins that might be present are known and is only really successful when an
organism’s genome has been sequenced. To this end, in recent years proteomics
has begun to be applied in bees towards understanding a range of paradigms.

Where is the future of
proteomics research in bees heading? Mapping protein expression across all
tissues and castes in adult bees is the logical next step after sequencing the
bee genome. The genome helps to determine which proteins may be present but
where are those proteins expressed? The protein expression atlas in bees will
tell that and will mark a significant step forward for bees as a model system
as this would be the first such comprehensive atlas in any multicellular
organism. Additional protein-based methods (protein extraction and immunochemical
assays for protein abundance) are covered in further detail in the BEEBOOK paper on physiology and
biochemistry (Hartfelder et al.,
2013).